Ontario (province): a portion of the northwest bordering northeastern Manitoba

Also, most of the province of Saskatchewan is on Central Standard Time year round, never adjusting for Daylight Saving Time. Major exceptions include Lloydminster, a city situated on the boundary between Alberta and Saskatchewan where the city charter stipulates that it shall observe Mountain Time and DST, putting the community on the same time as all of Alberta, including the major cities of Calgary and Edmonton.

The Central Time Zone is the second most populous in the US after the Eastern Time Zone. Many states straddle time zone boundaries.

Alabama: Although all of Alabama is legally on Central Time, Phenix City and the surrounding communities of Smiths Station, Valley, and Lanett unofficially observe Eastern Time, as these areas are part of the media market and metropolitan area of the considerably larger city of Columbus, Georgia in the Eastern Time Zone.[1]

Daylight saving time (DST) is in effect in much of the Central time zone between mid-March and early November. The modified time is called Central Daylight Time (CDT) and is UTC−5. In Canada, Saskatchewan does not observe a time change. One reason that Saskatchewan does not take part in a time change is that, geographically, the entire province is closer to the Mountain Time Zone's meridian. The province elected to move onto "permanent" daylight saving by being part of the Central Time Zone. The only exception is the region immediately surrounding the Saskatchewan side of the biprovincial city of Lloydminster, which has chosen to use Mountain Time with DST, synchronizing its clocks with those of Alberta.

In those areas of the Canadian and American time zones that observe DST, beginning in 2007, the local time changes at 02:00 local standard time to 03:00 local daylight time on the second Sunday in March and returns at 02:00 local daylight time to 01:00 local standard time on the first Sunday in November. Mexico decided not to go along with this change and observes their horario de verano from the first Sunday in April to the last Sunday in October. In December 2009, the Mexican Congress allowed ten border cities, eight of which are in states that observe Central Time, to adopt the U.S. daylight time schedule effective in 2010.